Monitoring groundwater level is like keeping a tab on your income and expenses—if you are spending more, it is a warning sign. You can cut down spending or find ways to earn more. Similarly, a city must decide whether to reduce extraction in certain areas or improve recharge methods, such as rainwater harvesting, wastewater treatment, or preserving open spaces. So, does Bengaluru have enough groundwater monitoring systems?
While a WELL Labs report estimates the city’s groundwater consumption as 1,392 million litres a day (MLD), BWSSB’s groundwater outlook report states that the extraction is only 800 MLD. This suggests a significant discrepancy in estimates, mostly because of insufficient data and inadequate monitoring points, highlighting the urgent need for proper tracking of groundwater resources.
Why is improved groundwater monitoring important
According to the groundwater resource assessment by the Central Ground Water Board (CGWB), groundwater resources are over-exploited at all 10 assessment units in Bengaluru Rural and Urban districts.
Sekhar M, a faculty member at the Indian Institute of Science’s Interdisciplinary Centre for Water Research (ICWaR), emphasises the need for optimal aquifer use by combining artificial and natural recharge. To achieve this, it is crucial to identify areas with high extraction and potential recharge sites, which requires monitoring at multiple points within a given region.
“Groundwater is not visible, and we can make the invisible visible only with data. With such local data, decision making becomes easier—to understand critical places, invest more in recharge and also reduce usage,” Sekhar points out.
Lack of adequate monitoring systems
While experts suggest one monitoring well for each ward, the numbers are much lower, which makes it difficult to track extraction.
According to Jayaprakash H P, head and Scientist D at the Southwestern Regional office of CGWB in Bengaluru, CGWB monitors around 35–40 deeper aquifers and 20–25 shallow aquifers every month. Among these, 18 digital recorders collect water level data every six hours. The rest are piezometers, which require manual intervention. The State groundwater authority also monitors around 30 to 35 wells with a combination of digital and manual monitoring stations.
Also, CGWB does not release monthly data; instead, it publishes seasonal data once every three months.
Challenges in ward-level monitoring
Jayaprakash states that CGWB faces manpower constraints, with only 25 employees handling all operations in Karnataka and Goa.
He adds that this is set to improve as there are plans to increase the monitoring. The CGWB, IISc and BWSSB together have signed a Memorandum of Understanding (MoU), and CGWB has recommended ward-wise groundwater level monitoring. BWSSB is procuring IoT (Internet of Things)-based groundwater monitoring systems to collect data on groundwater levels.
The CGWB acts as a technical advisor to the state departments and develops recommendations. Thus, the implementation is in the hands of BWSSB, for whom this is the first time taking up groundwater monitoring. The IoT-based monitoring project and a groundwater task force within BWSSB were announced in April 2024 but no progress has been made till now.
